First, California pecan growers accustomed to growing walnuts applied walnut production methods to pecans. Second, growers implemented successful management tools used in Mid-South and Southeast pecan groves.

“Growing pecans as walnut trees was a huge mistake. We learned this the hard way,” Blain said. “Production practices which fit well in other pecan areas did not work under the California climate.”

As the hardships unraveled, an extreme case of alternate bearing began in trees 10 years and older.

California growers faced severe infestations of the aphid complex including the yellow pecan aphid, Monelliosis pecanis, and the black margin aphid, Monellia caryella. Growers did not spray enough insecticide.

These aphids feed on the underside of leaves reducing photosynthesis. Large amounts of honeydew are left behind decreasing the leaf’s ability to mature.

To combat the pests, contact foliar insecticide sprays were applied every two to three weeks yet poor control resulted and product resistance followed. The result was a heavy buildup of honeydew which led to extreme cases of sooty mold which was aggravated by California’s lack of rainfall during the summer months.

Leaf analyses confirmed excess leaf temperatures. Leaves were too hot by noon which stopped the ability to store nutrients.

“These issues substantially reduced pecan quality,” Blain told the crowd. “We had difficulty finding buyers for the pecans.”

The trees towered to 50 to 60 feet at 20-years of age and crowded together to shade out the lower limbs. The extreme growth eliminated foliage and fruitwood within the first 15 feet of the tree. A pruning tower was necessary to reach the foliage to obtain petiole samples.

As a result of these many issues, kernel fill resembled the sinking Titanic as the percentage sank from 62 percent to about 50 percent.

Tree variety also contributed the demise. The industry’s initial tree plantings primarily were the successful Wichita variety. Cheyenne and Western Schley were planted as pollinators. In the end, Blain says Cheyenne was a poor choice for California.

Alternate bearing occurred on a tree-by-tree basis. At harvest, several trees in a row might produce 12,000 nuts each. The next tree over might produce a dozen nuts total.

Another factor involved the lack of natural nut drop during the California season. In other pecan-producing regions, two to three distinct nut drops per season was normal. No natural nut drop occurred in California pecan trees. Every nut set on the tree stayed until harvest - even in overloaded trees.

Trees planted in lighter, sandier soils had more problems.

California growers scratched their heads and began pulling out trees. About 25 percent of the trees planted in the ‘70s were removed and replaced with walnuts, almonds, pistachios.

In the late ‘90s, California growers entered survival mode. Production changes slowly launched a return to higher yields, improved nut quality, and profitability.

A tree thinning program was implemented to reduce the nuts per cluster to two to three pecans. Nuts were thinned at the 50-percent nut embryo stage; about one- to two-weeks before shell hardening.

Growers also implemented tree hedging. Blain traveled to Australia to learn more about hedging at Stahmann Farms, the largest pecan producer in the southern hemisphere. Once home, Blain initiated hedging the tree tops and sides of trees in every other middle row every other year.

California growers implemented Temik (Aldicarb) insecticide sprays to decrease the aphid population.

“Temik basically saved the California pecan industry,” Blain explained. “Once aphids were under control, our pecan world changed for the better.”

The Environmental Protection Agency has removed Temik from the market. Blain now uses Admire insecticide with good results.